Preheat oven to 400 degrees. In a medium saucepan, heat oil over medium; add cabbage and potatoes. Cook until beginning to brown, 7 to 9 minutes. Add beef; cook, breaking up meat with a spoon, until no longer pink, about 5 minutes. Stir in tomato paste, Worcestershire, thyme, and 1 cup water. Cover, and cook until potatoes are tender, about 15 minutes. Lightly mash mixture with a fork. Season with salt and pepper. Let cool completely.

On a lightly floured work surface, roll each crust into a 14-inch square; cut each into 4 equal squares. Place 1/2 cup filling on one half of each square, leaving a 1/2-inch border around the filling. Brush borders with water; fold dough over filling to enclose. Crimp edges with a fork to seal. With a paring knife or scissors, cut 3 small vents in each.

To freeze: Prepare through step 2. Arrange unbaked pies on a baking sheet (they should not touch); freeze until firm, about 1 hour. Wrap each pie in foil. Place in a resealable plastic bag; freeze up to 2 months.

To bake from frozen: Proceed with step 3, increasing baking time to 28 to 30 minutes.